A Laboratory Investigation of the Probable Mechanisms of the Action of an Artificial Thunderstorm Cell on Model Aircraft Radomes

The results of experimental laboratory investigations of possible mechanisms of the impact of lightning and thunderclouds on aircraft radomes and equipment inside them are presented. An artificial thunderstorm cell of negative polarity and model aircraft radomes with lightning diverter strips have been used. Experiments have shown that the discharge processes in a radome model significantly depend on the magnitude of the charge that accumulates on the inner and outer surfaces of the radome shell. It is established that the accumulation of large-magnitude charges of different signs on the outer and/or inner surface of the radome (up to hundreds of µC/m2) shell leads to a multivariance of the mechanisms of development of discharge processes inside the radome model, along its surface, and in the space near it. Significant influence of the “reverse” discharge from the antenna model under the radome on the types of current impulses recorded on the antennas under impact of the artificial thunderstorm cell is established. Peculiarities of the discharge formation in the radome model when using solid and segmented diverter strips for its protection are revealed. Parameters of the current impulses registered on the diverter strips and the antennas have been determined. Based on the conducted research, the possible mechanisms of the impact of thunderclouds and lightning discharges on radio-transparent aircraft radomes and the equipment inside them are considered.

The study of instabilities role of plasma in the high-voltage discharge formation initiated by optical radiation at high pressures in high-voltage optically triggered switches

The paper presents the experimental results of triggering a high-voltage gas gap by YAG: Nd3+ laser radiation. The gas gap was used as the primary switch of a high-current pulsed e-beam RADAN-type accelerator. As a result, an operating regime when the instability and delay time appeared to be minimal was experimentally found. The developed gas gap and the found operating regimes sustain the switching instability no more than 0.3 ns. The physical mechanisms determining the switch-on delay and the obtained level of instability are discussed.

DESIGN FEATURES AND THE TIME CHARACTERISTICS OF THE RAIL FOUR-CHANNEL SPARK GAP WITH FIELD DISTORTION

The article discusses the design features of a four-channel rail arrester with field distortion and the results of the study of its time characteristics. The need for this work related to the development of such dischargers due to the lack of their analogues is due to the widespread use of capacitive energy storage devices as power sources for electrodynamics mass accelerators. At the present stage of development of science and technology, the use of such accelerators is the most promising for creating experimental stands for modeling in laboratory conditions the processes of high-speed interaction of aircraft structural elements with particles of different masses and different origins. According to the operating conditions of the experimental stands and a wide range of changes in both particle masses and interaction velocities, the amplitude values of currents through the low-inductive load of the mass accelerator vary from hundreds of kilo amperes to several million amperes at acceleration times from units to hundreds of microseconds. With this in mind, capacitive energy storage devices are made in a multi-module design. Each module is switched to the load by its own switch. To extend the range of operation of the drive, provide the required erosion resistance of the electrodes of the switch, the stability of the discharge formation at parallel operation of switches developed construction of a rail four-channel spark gap with the distortion field, experimental and theoretical study of the effect of the ratio of the geometric dimensions of the inter electrode gap for obtaining small values for the delay time of the discharge. As a result of the research, it is shown that the value of the delay time tzap depends on the shape and diameter of the main electrodes, the material of the electrodes, the distance between the main and the control electrode, the threshold voltage, as well as the degree of inhomogeneity of the field in the inter electrode gap. The obtained analytical expressions allow us to determine the values of threshold stresses and delay times, taking into account the statistical delay time and the time of discharge formation. It is established that the value of the delay time is significantly affected by the field inhomogeneity coefficient and the configuration of the control electrode. It is noted that when the operating voltage on the arrester exceeds the threshold voltage, the delay time of the switch lies in the nanosecond region. The value of the threshold voltage Upor, at which the process of direct transformation of the streamer into a spark discharge with high conductivity, followed by a breakdown of the inter electrode gap, is determined.